laser

## Attributes for Laser Measurement

Before you get into the details of non-contact laser sensors, you need to understand their attributes to improve the results that you obtain when you use them for measurement. Laser sensors are excellent at gathering large amounts of data quickly. They are also good for measuring parts that may otherwise deform under the pressure of a tactile probe.

However, keep in mind that other factors, such as sunlight, surface finish, surface reflectivity, and surface color can influence measurements taken with laser sensors. To compensate for some of these factors, you can apply filters to the data to handle the influence. You should understand how and why these items affect the measurement results.

Sunlight

Unlike other non-contact systems, laser sensors are not generally affected by standard industrial lighting. Laser sensors work under varied lighting conditions because the sensor’s frequency is tuned to its own laser. Only light that has the same frequency as the laser itself can affect the measurement. Because sunlight contains all frequencies of light, it is important to keep sunlight out of the inspection room.

Surface Finish

Because tactile probes are larger than the deviation in most surface finishes, a tactile probe acts as an averaging filter. When the tactile probe contacts the surface, it gives an average of the highest points on the surface. When you use a laser sensor, the light reflects off the surface of the part. How the light reflects depends a lot on the roughness of the surface, even if it does not appear rough to human sight or touch.

Surface Reflectivity

Generally, surfaces with a matte finish work better than those with a glossy finish. A glossy surface finish usually has directional reflection. Based on the angle of the light, you can get too much or too little light. You might even get a "hot spot" (something that looks like a "blob" in the Graphic Display window). This blob is actually the image of the light source. The reflection of light might add some extraneous points to the scan line, but the rest of the points are not affected by the reflection. To compensate for surface reflectivity, you can spray the part with an aerosol powder or paint.

Surface Color

Because the laser is light, the surface color can potentially impact the measurement. Similar to how something colored black absorbs heat from the sun, black surfaces on a part absorb the laser's light and make the measurement of those surfaces difficult. Darker colors have more potential for problems than lighter colors. If your part is too dark, you can apply powder coatings to it to make it easier to sample.

It usually takes time and experience with your particular parts and in your specific environment to determine what settings work best for you. You should experiment with the capabilities of your specific sensor to improve the measurement results.

WARNING: Exercise caution when working with Laser sensors as they can damage your eyes. Consult your laser sensor documentation for safety issues and procedures for a safe work environment.